Factors which regulate the oxygenation of blood and tissues and the effects of lung diseases on systemic and pulmonary blood pressures are examined in this program. Studies in chronic diffuse interstitial lung diseases continue in an effort to identify the cause(s) of impaired hypoxic vasoconstriction in pulmonary vessels in these diseases and to delineate the contribution of disturbed oxygen diffusion to hypoxemia. The demonstration that respiratory muscle dysfunction is a cause of hypercapnia in patients with neuromuscular disorders in the absence of intrinsic lung diseases prompts continued investigation of the factors which may lead to this weakness not only in these patients but also in those with chronic pulmonary disorders. To further our understanding of the function of muscle myoglobin, its oxygen transport function will be examined during active muscular contraction under hypoxic conditions. In addition, the intracellular transport oxygen function of myoglobin in isolated cardiac muscle cells will be studied. Development of techniques for the ultrastructural localization of angiotensin converting enzyme tested. To further understanding of the basic controls of catecholamine-beta receptor interaction, beta-adrenergic receptors in cultured endothelial cells will be investigated.